      :relayed-event-topics topics
      :msg-fn (fn [prev [event]]
                (when (contains? topics (:topic event))
-                 (->Fresh (:value event))))}))
+                 (->Fresh (value event))))}))
 
 (defrecord Signal
   [init message-emitter deps event-sources]

                               (reductions msg-fn prev)
                               (into [] (comp cat (drop 1))))]
        (if (empty? output-series)
          [(->Cached (:value prev))]
          output-series)))))

; wiring up channels:

        msgs->events (comp cat
                           (filter fresh?)
                           (core/map (fn [msg]
                                       (->Event topic (value msg)))))
        events-channel-fn (fn [live-graph _]
                            (async/tap (get (:mult-map live-graph) source)
                                       (chan 1 msgs->events)))]
